Solder paste printing is a key process for modules such as Ball Attach (BA) modules and its quality control is one of the most critical tasks for second level inspection. However, there exist many challenges for the BA Solder Paste Inspection (SPI) process. Generally, the dimensions, geometry, color and transparency of solder paste materials can vary dramatically in the BA process. Therefore, a fast, precise and reliable post-printing SPI technique that can accurately inspect such parameters as flux and paste dispense to help insure a good solder joint for the BA module, despite such variation, is in demand. This demand can be met by the multi-level fluorescence imaging technique for organic materials disclosed herein.